Version: 2023.2
LanguageEnglish
  • C#

SearchExpressionEvaluatorAttribute Constructor

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Declaration

public SearchExpressionEvaluatorAttribute(params SearchExpressionType[] signatureArgumentTypes);

Declaration

public SearchExpressionEvaluatorAttribute(string name, params SearchExpressionType[] signatureArgumentTypes);

Declaration

public SearchExpressionEvaluatorAttribute(Search.SearchExpressionEvaluationHints hints, params SearchExpressionType[] signatureArgumentTypes);

Declaration

public SearchExpressionEvaluatorAttribute(string name, Search.SearchExpressionEvaluationHints hints, params SearchExpressionType[] signatureArgumentTypes);

Parameters

signatureArgumentTypes Array of types corresponding to the type of the parameters used with this evaluator.
name N ame of the evaluator. If no name are specified the name of the evaluator functio will be used.
hints Hints to specify to the evaluator runtime how function should be run.

Description

Use this attribute to register a static C# function as a new evaluator. SearchExpressionEvaluator when use within a SearchExpression can have a signature that is validated against the passed parameters.

Here is an example using a Variadic paramater.

[SearchExpressionEvaluator(SearchExpressionType.Iterable | SearchExpressionType.Variadic)]
[SearchExpressionEvaluatorSignatureOverload(SearchExpressionType.Number, SearchExpressionType.Iterable | SearchExpressionType.Variadic)]
[Description("Extract and returns the X first results for each expression.")]
public static IEnumerable<SearchItem> TakeXFirst(SearchExpressionContext c)
{
    var argIndex = 0;
    var takeNumber = 1;
    if (c.args[0].types.HasFlag(SearchExpressionType.Number))
    {
        ++argIndex;
        takeNumber = Math.Max((int)(c.args[0].GetNumberValue(takeNumber)), 0);
    }

    for ( ; argIndex < c.args.Length; ++argIndex)
    {
        var iterable = c.args[argIndex].Execute(c);
        var taken = 0;
        foreach (var item in iterable)
        {
            if (item == null)
                yield return null;
            else
            {
                yield return item;
                ++taken;
                if (taken == takeNumber)
                {
                    c.Break();
                    break;
                }
            }
        }
    }
}

Here is an example not supporting thread evaluation.

[Description("Returns ids of current selection")]
[SearchExpressionEvaluator(SearchExpressionEvaluationHints.ThreadNotSupported)]
public static IEnumerable<SearchItem> SelectionIds(SearchExpressionContext c)
{
    var instanceIds = UnityEditor.Selection.instanceIDs;
    foreach (var id in instanceIds)
    {
        yield return SearchExpression.CreateItem(id, c.ResolveAlias("selected id"));
    }
}